Signal path termination

ABSTRACT

This disclosure relates to a harmonic termination circuit that is separate from a load line. In one embodiment, the load line is configured to match an impedance at the power amplifier output at a fundamental frequency of the power amplifier output and the harmonic termination circuit is configured to terminate at a phase corresponding to a harmonic frequency of the power amplifier output. According to certain embodiments, the load line and the harmonic termination circuit can be electrically coupled to the power amplifier output external to a power amplifier die via different output pins of the power amplifier die.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/543,472 filed on Jul. 6, 2012, titled “SIGNAL PATH TERMINATION,” theentire disclosure of which is hereby incorporated by reference herein inits entirety. This application claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Patent Application No. 61/505,956 filed onJul. 8, 2011, titled “SIGNAL PATH TERMINATION,” the disclosure of whichis hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The disclosed technology relates to terminating a harmonic component ofa signal.

2. Description of the Related Technology

In relatively high frequency applications, such as radio frequency (RF)applications, unwanted signal reflection and/or noise can occur. Suchunwanted signal reflection and/or noise can occur at a fundamentalfrequency of the signal and/or other frequencies, such as harmonics ofthe fundamental frequency of the signal. To reduce the impact of signalreflection and/or noise, impedance matching can be implemented. Oneillustrative application in which it is advantageous to minimizeunwanted signal reflection and/or noise is a power amplifier system.

Power added efficiency (PAE) is one metric for rating power amplifiers.In addition, linearity is another metric for rating power amplifiers.PAE and/or linearity can be metrics by which customers, such as originalequipment manufacturers (OEMs), determine which power amplifiers topurchase. For instance, power amplifiers with a PAE below a certainlevel may not be purchased by a customer due to the impact of PAE on thecustomer's product. A lower PAE can, for example, reduce the batterylife of an electronic device, such as a mobile phone. However, enhancingPAE can come at the cost of adversely impacting linearity. Similarly,improving linearity can cause a decrease in PAE. At the same time,customers want power amplifiers with high linearity and high PAE.

A load line at an output of a power amplifier can impact both PAE andlinearity. Some conventional power amplifier systems have included aload line to match an impedance of the power amplifier output at afundamental frequency of the power amplifier output signal and also toperform harmonic termination. However, it has proved difficult to matchan impedance of the fundamental frequency of the power amplifier outputwhile including harmonic termination in a way that optimizes both PAEand linearity. Accordingly, a need exists to improve both linearity andPAE of a power amplifier.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of this invention, some prominent featureswill now be briefly discussed.

One aspect of the disclosure is a power amplifier module including apower amplifier die, a load line, and a harmonic termination circuit.The power amplifier die includes one or more power amplifiers configuredto amplify an input signal at a power amplifier input and to generate anamplified output signal at a power amplifier output. The power amplifierdie also has a plurality of output pins. The load line is configured tomatch an impedance at the power amplifier output at a fundamentalfrequency of the amplified output signal. The load line is electricallycoupled to a first group of one or more of the plurality of output pinsof the power amplifier die external to the power amplifier die. Theharmonic termination circuit is separate from the load line. Theharmonic termination circuit is configured to terminate at a phasecorresponding to a harmonic frequency of the amplified output signal.The harmonic termination circuit is electrically coupled to a secondgroup of one or more other pins of the plurality of output pins of thepower amplifier die external to the power amplifier die.

In certain implementations, the harmonic termination circuit can includeone or more interconnects coupled to the second group of one or moreother pins of the power amplifier die external to the power amplifierdie. According to some of these implementations, the one or moreinterconnects can include a wirebond. Alternatively or additionally, theload line can include one or more other interconnects coupled to thefirst group of one or more pins of the power amplifier die external tothe power amplifier die. In accordance with various implementations, adifferent number of interconnects can be coupled to the first group ofone or more pins of the power amplifier die than to the second group ofone or more other pins of the power amplifier die.

According to a number of implementations, the first group of one or morepins of the power amplifier die can be electrically coupled to a firstconductive trace on a substrate and the second group of one or more pinsof the power amplifier die is electrically coupled to a secondconductive trace on the substrate, in which the first conductive traceis included in a different signal path than the second conductive traceexternal to the power amplifier die. In some of these implementations,the harmonic termination circuit can include a wirebond having a firstend and a second end, the first end coupled to the second first group ofone or more pins of the power amplifier die; the second conductive traceon the substrate, the second conductive trace coupled to the second endof the wirebond; and a capacitor having a first end and a second end,the first end coupled to the second conductive trace and the second endcoupled to a reference voltage.

The harmonic frequency of the amplified output signal can be, forexample, a second harmonic frequency of the amplified output signal or athird harmonic frequency of the amplified output signal.

According to various implementations, the power amplifier module canalso include an other harmonic termination circuit separate from boththe load line and the harmonic termination circuit, the other harmonictermination circuit configured terminate at a phase corresponding to another harmonic frequency of the amplified output signal. The harmonictermination circuit can be in parallel with the other harmonictermination circuit, according to certain implementations.

The power amplifier module can also include an input matching networkconfigured to match an impedance at the power amplifier input and aseparate harmonic termination circuit configured to terminate at a phaseof a harmonic frequency of the input signal, according to certainimplementations.

In some implementations, a portion of the harmonic termination circuitcan be implemented within the power amplifier die.

Another aspect of this disclosure is a mobile device that includes abattery configured to power the mobile device, a power amplifier die, aload line, a harmonic termination circuit, and an antenna electricallycoupled to the load line, the antenna configured to transmit anamplified RF signal. The power amplifier die includes a power amplifierconfigured to amplify a radio frequency (RF) input signal received at apower amplifier input node and to generate the amplified RF signal at apower amplifier output node. The load line is configured to match animpedance at the power amplifier output node at a fundamental frequencyof the amplified RF signal. The harmonic termination circuit is separatefrom the load line. The harmonic termination circuit is configured toterminate at a phase corresponding to a harmonic frequency of theamplified RF signal. The harmonic termination circuit and the load linehave different electrical connections to the power amplifier output nodeexternal to the power amplifier die.

Another aspect of this disclosure is an apparatus that includes a dieand a substrate configured to receive the die. The die includes at leastone active circuit element configured to drive an output signal to anoutput node. The substrate includes a first conductive trace and asecond conductive trace. The first conductive trace and the secondconductive trace are part of different signal paths on the substrate.The first conductive trace is included in a load line configured tomatch an impedance at output node of the die at a fundamental frequencyof the output signal. The second conductive trace is included in aharmonic termination circuit separate from the load line. The harmonictermination circuit is configured to terminate at a phase correspondingto a harmonic frequency of the output signal.

In certain implementations, the substrate can include a third conductivetrace, which is included in an other harmonic termination circuitconfigured to terminate at a phase corresponding to a different harmonicfrequency of the output signal.

According to some implementations, the apparatus can also include awirebond configured to electrically couple the output node of the die tothe second conductive trace, and the wirebond can be included in theharmonic termination circuit.

In accordance with a number of implementations, the apparatus can alsoinclude a capacitor mounted to the substrate, in which the capacitor iselectrically coupled to the second conductive trace and the capacitor isincluded in the harmonic termination circuit.

Yet another aspect of this disclosure is a method of manufacturing amodule. The method includes coupling power amplifier die to a packagingsubstrate, the power amplifier die including a power amplifierconfigured to receive an input signal and generate an amplified outputsignal; forming a first interconnect between the power amplifier die anda first conductive trace on the packaging substrate, the firstinterconnect being included in a first termination circuit configured tomatch an impedance of a fundamental frequency of the amplified outputsignal; and forming a second interconnect between the power amplifierdie and a second conductive trace on the packaging substrate, the secondinterconnect being separate from the first interconnect, the firstconductive trace being separate from the second conductive trace, andthe second interconnect being included in a second termination circuitconfigured to terminate at a phase corresponding to a harmonic of theamplified output signal.

In some implementations, forming the first interconnect can includewirebonding a pad of the power amplifier die to the first conductivetrace on the packaging substrate.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic block diagram of an illustrative wireless device.

FIG. 1B is a schematic block diagram of another illustrative wirelessdevice.

FIG. 1C is a schematic block diagram of an illustrative power amplifiermodule.

FIG. 2 is a circuit diagram illustrating a power amplifier system withexample termination circuits according to an embodiment.

FIG. 3A is a block diagram illustrating an example power amplifiermodule with termination circuits according to another embodiment.

FIG. 3B illustrates an example substrate in accordance with anembodiment.

FIGS. 4A-4C show simulation results comparing performance of theembodiment of FIG. 3A to a conventional implementation.

FIG. 5 is a block diagram illustrating a die and example terminationcircuits according to another embodiment.

FIG. 6 is a flow diagram of an illustrative method of manufacturing amodule according to yet another embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Generally described, aspects of the present disclosure relate tocircuits configured to prevent reflection(s) of a signal, such astermination circuits. More specifically, aspects of the presentdisclosure relate to separate termination circuits configured to preventportions of the power of different frequency components of a signal frombeing reflected. Using the systems, apparatus, and methods describedherein, electronic systems, such as systems that include a poweramplifier and/or systems configured to transmit radio frequency (RF)signals, can operate more efficiently and/or consume less power. Forinstance, less energy can be converted to harmonic frequencies of an RFsignal and/or energy from harmonic frequency components of an RF signalcan be converted into energy at a fundamental frequency of the RFsignal. In accordance with one or more features described herein, directcurrent (DC) energy can be more efficiently converted into RF energy.

As discussed above, customers, such as original equipment manufacturers(OEMs), often desired high PAE and high linearity. A load line at anoutput of a power amplifier can impact PAE and linearity. The load lineat the output power amplifier can be configured to increase and/oroptimize linearity and/or PAE. This can include matching fundamentalfrequency components and/or terminating one or more harmonic frequencycomponents of the power amplifier output. Such a load line can beimplemented by termination circuits.

A power amplifier output can include a fundamental frequency componentand one or more harmonic frequency components. Similarly, an input to apower amplifier or a power amplifier stage can include a fundamentalfrequency component and one or more harmonic frequency components. Someconventional power amplifier systems have included a single terminationcircuit (e.g., a load line) to match an impedance of a fundamentalfrequency of the signal at the node and terminate at a phasecorresponding to a harmonic frequency of the signal at the node.However, it can be difficult to tune the single termination circuit toboth match an impedance of the fundamental frequency of an amplifiedpower amplifier output signal and terminate at a phase of a harmonicfrequency of the amplified power amplifier output signal in a way thatoptimizes both PAE and linearity. As a result, PAE can decrease due tooptimizing either matching an impedance of the fundamental frequency ofamplified power amplifier output or terminating the amplified poweramplifier output at a phase of the harmonic frequency.

As described herein, an electronic system can include two or moreseparate termination circuits each coupled to a node in a signal path,such as a power amplifier output or an input to a power amplifier stage.A first termination circuit can be configured to match an impedance of afundamental frequency of a signal at a node. In some implementations,the first termination circuit can be included in a fundamental loadline. A second termination circuit, separate from the first terminationcircuit, can be configured to terminate at a phase corresponding to aharmonic frequency of the signal at the node. Circuit elements of thefirst termination circuit and the second termination circuit can beselected so as to improve PAE and linearity in a power amplifier system.

In some implementations, at least a portion of the first terminationcircuit and/or the second termination circuit can be embodied externalto a die that includes the circuit element(s) driving an output node ofthe die, such as a power amplifier output of a power amplifier die. Forexample, the first termination circuit can include one or moreinterconnects, such as wire bonds, electrically connected to one or morepins of a power amplifier die coupled to a packaging substrate and oneor more capacitors separate from the power amplifier die and coupled tothe packaging substrate. Alternatively or additionally, the secondtermination circuit can include one or more interconnects, such as wirebonds, electrically connected to one or more pins of the power amplifierdie and one or more other capacitors coupled to a packaging substrate.When a plurality of interconnects are included in a termination circuit,the interconnects can be coupled in parallel with each other. In atleast one of the first termination circuit and the second terminationcircuit, one or more wire bonds can function as an inductive circuitelement and be coupled in series with the one or more capacitors coupledto the packaging substrate.

External to the die, the first termination circuit and the secondtermination circuit can have different electrical connections to theoutput node of the die. In certain implementations, a first output pinof the die can be coupled to the first termination circuit by a firstwirebond and a second output pin of the die can be coupled to the secondtermination circuit by a second wirebond. In some of theseimplementations, a first number of wirebonds can couple the firsttermination circuit to pins of the die and a second number of wirebondscan couple the second termination circuit to pins of the die, in whichthe first number is different than the second number. According to anumber of other implementations, a first output pin of the die can becoupled to the first termination circuit by a first bump and a secondoutput pin of the die can be coupled to the second termination circuitby a second bump. In some of these implementations, a first number ofbumps can couple the first termination circuit to pins of the die and asecond number of bumps can couple the second termination circuit to pinsof the die, in which the first number is different than the secondnumber.

The first termination circuit and the second termination circuit caninclude different signal paths external to the die. For instance, thefirst termination circuit termination circuit can include a first traceimplemented on the packaging substrate and the second terminationcircuit can include a second trace on the substrate. The first trace andthe second trace can be part of separate signal paths on the substrate.For instance, in some implementations, the first trace can be part of anRF signal path and the second trace can be part of a DC signal path. Thefirst trace and the second trace can be electrically separate from eachother outside of the die.

Alternatively or additionally, within the die, the output node can beelectrically coupled to branching conductive features such that theoutput is provided to separate signal paths on the die. The separatesignal paths can include a first path included in the first terminationcircuit and a second path included in the second termination circuit. Inthis way, the first termination circuit and the second terminationcircuit can be separately tunable within the die during design of thedie. For instance, the first signal path in the die can lead to a firstoutput pin of the die and the second signal path can include a capacitorimplemented on the die before leading to a second output pin. In oneembodiment, a collector of an output stage of a power amplifier can bedirectly electrically coupled to both the first termination circuit andthe second termination circuit by conductive features of the die.

By using two or more separate termination circuits, each terminationcircuit can be tuned to prevent reflection of the signal at a desiredfrequency. For instance, the inductance and/or capacitance of eachtermination circuit can be selected such that each termination circuitprevents reflect of a desired frequency component of a signal.

The methods, systems, and apparatus for signal path terminationdescribed herein may be able to achieve one or more of the followingadvantageous features, among others. Advantageously, the separatetermination circuits configured to prevent reflection of two or moredistinct frequency components of a signal can increase one or more ofPAE, linearity of a power amplifier, and baseband performance (forexample, a broader frequency response and/or greater bandwidth). In someimplementations, both PAE and linearity of the power amplifier can beincreased. Furthermore, the figure of merit (FOM) of a power amplifiercan also be increased. Moreover, battery life can be extended, an amountof heat dissipated can be reduced, signal quality of the signal uponwhich the separate termination circuits are preventing reflection can beincreased, or any combination thereof.

The headings provided herein are for convenience only and do notnecessarily affect the scope or meaning of the claims.

Wireless Devices

Any of the systems, methods, apparatus, and systems for preventingreflection of two or more frequency components of a signal describedherein can be implemented in a variety of electronic devices, such as awireless device or a mobile device. FIG. 1A schematically depicts awireless device 1. Examples of the wireless device 1 include, but arenot limited to, a cellular phone (e.g., a smart phone), a laptop, atablet computer, a personal digital assistant (PDA), an electronic bookreader, and a portable digital media player. For instance, the wirelessdevice 1 can be a multi-band and/or multi-mode device such as amulti-band/multi-mode mobile phone configured to communicate using, forexample, Global System for Mobile (GSM), code division multiple access(CDMA), 3G, 4G, long term evolution (LTE), the like, or any combinationthereof.

In certain embodiments, the wireless device 1 can include an RF frontend 2, a transceiver component 3, an antenna 4, power amplifiers 5, acontrol component 6, a computer readable medium 7, a processor 8, abattery 9, and a supply control block 10, or any combination thereof.

The transceiver component 3 can generate RF signals for transmission viathe antenna 4. Furthermore, the transceiver component 3 can receiveincoming RF signals from the antenna 4.

It will be understood that various functionalities associated with thetransmission and receiving of RF signals can be achieved by one or morecomponents that are collectively represented in FIG. 1 as thetransceiver 3. For example, a single component can be configured toprovide both transmitting and receiving functionalities. In anotherexample, transmitting and receiving functionalities can be provided byseparate components.

Similarly, it will be understood that various antenna functionalitiesassociated with the transmission and receiving of RF signals can beachieved by one or more components that are collectively represented inFIG. 1 as the antenna 4. For example, a single antenna can be configuredto provide both transmitting and receiving functionalities. In anotherexample, transmitting and receiving functionalities can be provided byseparate antennas. In yet another example, different bands associatedwith the wireless device 1 can be provided with different antennas.

In FIG. 1, one or more output signals from the transceiver 3 aredepicted as being provided to the antenna 4 via one or more transmissionpaths. In the example shown, different transmission paths can representoutput paths associated with different bands and/or different poweroutputs. For instance, the two example power amplifiers 5 shown canrepresent amplifications associated with different power outputconfigurations (e.g., low power output and high power output), and/oramplifications associated with different bands. In some implementations,one or more termination circuits can be included in one or more of thetransmission paths.

In FIG. 1, one or more detected signals from the antenna 4 are depictedas being provided to the transceiver 3 via one or more receiving paths.In the example shown, different receiving paths can represent pathsassociated with different bands. For example, the four example pathsshown can represent quad-band capability that some wireless devices areprovided with.

To facilitate switching between receive and transmit paths, the RF frontend 2 can be configured to electrically connect the antenna 4 to aselected transmit or receive path. Thus, the RF front end 2 can providea number of switching functionalities associated with an operation ofthe wireless device 1. In certain embodiments, the RF front end 2 caninclude a number of switches configured to provide functionalitiesassociated with, for example, switching between different bands,switching between different power modes, switching between transmissionand receiving modes, or some combination thereof. The RF front end 2 canalso be configured to provide additional functionality, includingfiltering of signals. For example, the RF front end 2 can include one ormore duplexers. Moreover, in some implementations, the RF front end 2can include one or more termination circuits configured to preventreflection of a frequency component of a signal.

The wireless device 1 can include one or more power amplifiers 5. RFpower amplifiers can be used to boost the power of a RF signal having arelatively low power. Thereafter, the boosted RF signal can be used fora variety of purposes, included driving the antenna of a transmitter.Power amplifiers 5 can be included in electronic devices, such as mobilephones, to amplify a RF signal for transmission. For example, in mobilephones having a an architecture for communicating under the 3G and/or 4Gcommunications standards, a power amplifier can be used to amplify a RFsignal. It can be desirable to manage the amplification of the RFsignal, as a desired transmit power level can depend on how far the useris away from a base station and/or the mobile environment. Poweramplifiers can also be employed to aid in regulating the power level ofthe RF signal over time, so as to prevent signal interference fromtransmission during an assigned receive time slot. A power amplifiermodule can include one or more power amplifiers.

FIG. 1 shows that in certain embodiments, a control component 6 can beprovided, and such a component can be configured to provide variouscontrol functionalities associated with operations of the RF front end2, the power amplifiers 5, the supply control 10, and/or other operatingcomponent(s).

In certain embodiments, a processor 8 can be configured to facilitateimplementation of various processes described herein. For the purpose ofdescription, embodiments of the present disclosure may also be describedwith reference to flowchart illustrations and/or block diagrams ofmethods, apparatus (systems) and computer program products. It will beunderstood that each block of the flowchart illustrations and/or blockdiagrams, and combinations of blocks in the flowchart illustrationsand/or block diagrams, may be implemented by computer programinstructions. These computer program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the acts specified in the flowchart and/or block diagramblock or blocks.

In certain embodiments, these computer program instructions may also bestored in a computer-readable memory 7 that can direct a computer orother programmable data processing apparatus to operate in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instructions whichimplement the acts specified in the flowchart and/or block diagram blockor blocks. The computer program instructions may also be loaded onto acomputer or other programmable data processing apparatus to cause aseries of operations to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide operations for implementing the acts specified in aflowchart and/or block diagram block or blocks.

The illustrated wireless device 1 also includes the supply control block10, which can be used to provide a power supply to one or more of thepower amplifiers 5. For example, the supply control block 10 can be aDC-to-DC converter. However, in certain embodiments the supply controlblock 10 can include other blocks, such as, for example, an envelopetracker configured to vary the supply voltage provided to the poweramplifiers 5 based upon an envelope of the RF signal to be amplified.

The supply control block 10 can be electrically connected to the battery9, and the supply control block 10 can be configured to vary the voltageprovided to the power amplifiers 5 based on an output voltage of a DC-DCconverter. The battery 9 can be any suitable battery for use in thewireless device 1, including, for example, a lithium-ion battery. Byreducing reflection of an output signal of the power amplifiers 5, thepower consumption of the battery 9 can be reduced, thereby improvingperformance of the wireless device 1. For instance, the terminationcircuits described herein can extend an amount of time that it takes thebattery 9 to discharge.

FIG. 1B is a schematic block diagram of an another illustrative wirelessdevice 30, which can implement one or more aspects of this disclosure.In some implementations, the illustrative wireless device 30 of FIG. 1Bcan be a mobile phone. Any combination of features of the terminationcircuits described herein can be implemented in connection with poweramplifiers, for example, in the 2.5G module and/or the 3G/4G front endmodules (FEMs) of the wireless device 30.

The illustrated wireless device 30 includes a main antenna 31, a switchmodule 32, a 2.5 G module 33, a 3G/4G front end module 34, an LNA module35, a diversity antenna 36, a diversity front end module 37, atransceiver 38, a global positioning system (GPS)_antenna 39, a powermanagement controller 40, a base band application processor 41, a memory42, a user interface 43, an accelerometer 44, a camera 45, a WLAN/FMBluetooth System on a Chip (SOC) 46, a WLAN Bluetooth antenna 47, and anFM antenna 48. It will be understood that the wireless device 30 caninclude more or fewer components than illustrated in FIG. 1B.

The transceiver 38 can be a multi-mode transceiver. The transceiver 38can be used to generate and process RF signals using a variety ofcommunication standards, including, for example, Global System forMobile Communications (GSM), Code Division Multiple Access (CDMA),wideband CDMA (W-CDMA), Enhanced Data Rates for GSM Evolution (EDGE),other proprietary and non-proprietary communications standards, or anycombination thereof. As illustrated, the transceiver 38 is electricallycoupled to the 2.5G Module 33 and the 3G/4G front end module 34. A poweramplifier in the 2.5G Module 33 and the 3G/4G front end module 34 canboost the power of an RF signal having a relatively low power.Thereafter, the boosted RF signal can be used to drive the main antenna31. Such power amplifiers can include any of the termination circuitsdescribed herein to reduce reflection and/or noise at an input and/or anoutput. The switch module 32 can selectively electrically coupled poweramplifiers in the 2.5G Module 33 and the 3G/4G front end module 34 tothe main antenna 31. The switch module 32 can electrically connect themain antenna 31 to a desired transmit path.

In certain implementations, the diversity front-end module 37 and thediversity antenna 36 can help improve the quality and/or reliability ofa wireless link by reducing line-of-sight losses and/or mitigating theimpacts of phase shifts, time delays and/or distortions associated withsignal interference of the main antenna 31. In some embodiments, aplurality of diversity front-end modules and diversity antennas can beprovided to further improve diversity.

The wireless device 30 can include the WLAN/FM Bluetooth SOC module 46,which can generate and process received WLAN Bluetooth and/or FMsignals. For example, the WLAN/FM Bluetooth SOC module 46 can be used toconnect to a Bluetooth device, such as a wireless headset, and/or tocommunicate over the Internet using a wireless access point or hotspotvia the WLAN Bluetooth antenna 47 and/or the FM antenna 48.

The wireless device 30 can also include a baseband application processor41 to process base band signals. A camera 43, an accelerometer 44, auser interface 45, the like, or any combination thereof can communicatewith the baseband application processor 41. Data processed by thebaseband application processor can be stored in the memory 42.

Although termination circuits have been illustrated and described in thecontext of two examples of wireless devices, the termination circuitsdescribed herein can be used in other wireless devices and electronics.

Modules

FIG. 1C is a schematic block diagram of a power amplifier module 20.Although a power amplifier module having a power amplifier die will bediscussed for illustrative purposes, it will be understood that theprinciples and advantages described herein can be applied to anysuitable die and/or any suitable electronic module. The power amplifiermodule 20 can include some or all of a power amplifier system. The poweramplifier module 20 can be referred to as multi-chip module in certainimplementations. The power amplifier module 20 can include a packagingsubstrate 22, one or more power amplifier die 24, a matching network 25,one or more other die 26, and one or more circuit elements 28 coupled tothe packaging substrate 22, the like, or any combination thereof.

The one or more other dies 26 can include, for example, a controllerdie, which can include a power amplifier bias circuit and/or a directcurrent-to-direct current (DC-DC) converter. Example circuit element(s)28 mounted on the packaging substrate can include, for example,inductor(s), capacitor(s), the like, or any combination thereof. Thepower amplifier module 20 can include a plurality of dies and/or othercomponents attached to and/or coupled to the packaging substrate 22 ofthe power amplifier module 20. In some implementations, the substrate 22can be a multi-layer substrate configured to support the dies and/orother components and to provide electrical connectivity to externalcircuitry when the power amplifier module 20 is mounted on a circuitboard, such as a phone board. Thus, the substrate 22 can be configuredto receive a plurality of components, such as die and/or separatepassive components. The substrate 22 can be a laminate substrate with afinish plating.

The power amplifier die 24 can receive a RF signal at one or more inputpins of the power amplifier module 20. The power amplifier die 24 caninclude one or more power amplifiers, including, for example,multi-stage power amplifiers configured to amplify the RF signal. Theamplified RF signal can be provided to one or more output pins of thepower amplifier die 24. The one or more output pins can be, for example,bond pad configured for wirebonding. The matching network 25 can beprovided on the power amplifier module 20 to aid in reducing signalreflections and/or other signal distortions. The matching network 25 caninclude one or more termination circuits that implement any combinationof features described herein. While the matching network is shown asexternal to the power amplifier die 24, it will be understood that atleast a portion of the matching network 25 can be implemented on thepower amplifier die 24. The power amplifier die 24 can be any suitabledie. In some implementations, the power amplifier die is a galliumarsenide (GaAs) die. In some of these implementations, the GaAs die hastransistors formed using a heterojunction bipolar transistor (HBT)process.

The one or more circuit elements 28 of the power amplifier module 20 caninclude a capacitor and an inductor. An inductor 28 can be implementedon the substrate 22 as a trace on the substrate 22 or as a surface mountcomponent (SMC) mounted to the substrate 22. The inductor can operate asa choke inductor, and can be disposed between a supply voltage receivedon a supply voltage pin V_(CC) and the power amplifier die 24. Theinductor can provide a power amplifier on the power amplifier die 24with a supply voltage received on the supply voltage pin V_(CC) whilechoking and/or blocking high frequency RF signal components. Theinductor can include a first end electrically connected to the supplyvoltage pin V_(CC), and a second end electrically connected to acollector of a bipolar transistor associated with the power amplifierdie 24. The capacitor can function as a decoupling capacitor. Thecapacitor can include a first end electrically connected to the firstend of the inductor and a second end electrically coupled to ground,which in certain implementations is provided using a ground pin of thepower amplifier module 20 (not illustrated). The capacitor can provide alow impedance path to high frequency signals, thereby reducing the noiseof the power amplifier supply voltage, improving power amplifierstability, and/or improving the performance of the inductor as a RFchoke. In some implementations, the capacitor can include a SMC.

The matching network 25 can include two or more termination circuits. Insome implementations, the matching network 25 can include wire bonds toelectrically connect input and/or output pins of the power amplifier die24 to the packaging substrate 22. The wire bonds can function asinductive circuit elements. The inductance can be increased by addingadditional wire bonds in parallel. The wirebonds in parallel can each becoupled to a different pin of the power amplifier die 24. The inductancecan be decreased by removing parallel wire bonds and/or adding wirebonds in series. The matching network 25 can also include one or moreconductive traces on the substrate 22 and one or more capacitors mountedon the substrate 22. Each termination circuit can include conductivetrace(s) and/or capacitor(s) in series with one or more wire bondselectrically connected to one or more pins of the power amplifier die24. The capacitance and/or inductance values can be selected so as toprevent certain frequency components from being reflected (for example,from an antenna) due to impedance mismatches. This can advantageouslyincrease PAE, power amplifier linearity, bandwidth over which the poweramplifier operates within a specification, FOM, the like, or anycombination thereof. Termination circuits that can be included in thematching network 25 will be described in more detail herein.

The power amplifier module 20 can be modified to include more or fewercomponents, including, for example, additional power amplifier dies,capacitors and/or inductors. For instance, the power amplifier module 20can include one or more additional matching networks 25. In particularthere can be another matching network between RF_IN and an input to thepower amplifier die 24 and/or an additional matching network betweenpower amplifier stages. As another example, the power amplifier module20 can include an additional power amplifier die, as well as anadditional capacitor and inductor configured to operate as an LC circuitdisposed between the additional power amplifier die and the V_(CC) pinof the module. The power amplifier module 20 can be configured to haveadditional pins, such as in implementations in which a separate powersupply is provided to an input stage disposed on the power amplifier dieand/or implementations in which the multi-chip module operates over aplurality of bands.

Termination Circuits

As used herein, a termination circuit can refer to a circuit configuredto prevent a portion of the power of a signal, such as an RF signal,from being reflected. A termination circuit can be configured to reduceand/or minimize reflections of the signal by matching impedance. Thiscan increase PAE and/or power amplifier gain. Termination circuits caninclude, for example, a load line configured to match an impedance of afundamental frequency at a node and one or more harmonic terminationcircuits.

With reference to FIG. 2, a circuit diagram of a power amplifier systemwith example termination circuits will be described. Some or all of thepower amplifier system can be implemented on a power amplifier module20. The power amplifier module 20 can include power amplifier stages 62and/or 64 such as GaAs bipolar transistors, power supply pins such as aV_(SUP1) and V_(SUP2), inductors 68 and/or 70, matching and V_(SUP2),networks 25 a, 25 b, and input matching circuit 29, or any combinationthereof. An RF input signal RF_IN can be provided to a first stage poweramplifier 62 via an input matching circuit 29. A first stage amplifiedRF signal can be generated by the first stage power amplifier 62. Thefirst stage amplified RF signal can be provided to the second stagepower amplifier 64 via an inter stage power amplifier matching network25 a 1. A second stage amplified RF signal can be generated by thesecond stage power amplifier 64. The second stage amplified RF signalcan be provided to an output load via an output matching network 25 b 1.The RF signal RF_OUT provided to the output load can be provided to anoutput of a power amplifier module in some implementations.

The first stage power amplifier 62 can be coupled to a power supply, forexample, the battery 66, via the choke inductor 68. Similarly, thesecond stage amplifier 64 can be coupled to the power supply, forexample, the battery 66, via the choke inductor 70. The first poweramplifier stage 62 can consume less power from the power supply whencorresponding termination circuits are tuned to prevent reflections of afundamental frequency component of the first stage amplified RF signaland one or more harmonic components of the first stage amplified RFsignal. Similarly, the second power amplifier stage 64 can consume lesspower from the power supply when corresponding termination circuits aretuned to prevent reflections of a fundamental frequency component of thesecond stage amplified RF signal and one or more harmonic components ofthe second stage amplified RF signal.

As illustrated in FIG. 2, the power amplifier module 20 can include afirst matching network 25 a and a second matching network 25 b. Thefirst matching network 25 a can include the inter stage fundamentaltermination circuit 25 a 1 and an inter stage harmonic terminationcircuit 25 a 2. The second matching network 25 b can include the outputfundamental termination circuit 25 b 1 and an output harmonictermination circuit 25 b 2. Any combination of features of secondmatching network 25 b can be applied to the first matching network 25 a,as appropriate.

For illustrative purposes, the second matching network 25 b will bedescribed in more detail. The output fundamental termination circuit 25b 1 can be a fundamental load line. The output fundamental terminationcircuit 25 b 1 can be configured to prevent a portion of the power of afundamental frequency component of the second stage amplified RF signalfrom being reflected from the load. The load can include, for example,an RF switch in a switch module 32 and an antenna 31. The outputharmonic termination circuit 25 b 2 can be configured to prevent aportion of the power of one or more harmonic frequency components of thesecond stage amplified RF signal from being leaked toward a load. Morespecifically, the output harmonic termination circuit 25 b 2 can includea termination circuit configured to prevent a portion of the power asecond order harmonic frequency component of the second stage amplifiedRF signal from being leaked toward the load. In some implementations,the output harmonic termination circuit 25 b 2 can alternatively oradditionally include a termination circuit configured to prevent aportion of the power a third order harmonic frequency component of thesecond stage amplified RF signal from being leaked toward the load. Theprinciples and advantages of separate termination circuits configured toprevent reflection of a portion of the power a harmonic frequencycomponent of the second stage amplified RF can be applied to any desiredharmonic frequency component and/or any suitable number of harmonicfrequency components. Although some embodiments are described withreference to harmonic frequencies, one or more features described hereincan be applied to any desired frequency.

A termination circuit corresponding to a desired frequency component ofthe second stage amplified RF signal can include one or more inductivecircuit elements in series with one or more capacitive circuit elements.The series circuit elements of the termination circuit can couple aninput node of a fundamental load line, such as the output fundamentaltermination circuit 25 b 1, to a ground reference voltage. The seriescircuit elements can include, for example, a wirebond, a trace on thesubstrate, and a surface mounted capacitor. In certain implementations,the series circuit elements can include a wirebond having a first endcoupled to an output pin of a die and a second end coupled to aconductive trace on a packaging substrate. According to some of theseimplementations, the series circuit elements can also include acapacitor mounted on the packaging substrate. Such a capacitor can havea first end coupled to the conductive trace and a second end coupled toa reference voltage, such as a ground potential. An effective inductanceof the inductive circuit element(s) and/or an effective capacitance ofthe capacitive circuit element(s) can be selected so as to tune thetermination circuit to prevent reflections of the desired frequencycomponent of the second stage amplified RF signal.

At node n1, the power amplifier output can include a fundamentalfrequency component and one or more harmonic frequency components. TheRF output signal RF_OUT provided to the output load can be the sum ofeach of these frequency components. A power amplifier output having awaveform that is efficient for transmitting a signal can result in adesirable linearity of the power amplifier. For instance, it can bedesirable to have the frequency components of the power amplifier outputat node n1 to combine to form a perfect sine wave. Alternatively oradditionally, it ca be desirable to prevent the output at the collectorof the bipolar transistor of the power amplifier output stage 64 fromclipping.

The impedance at node n1 can be represented by Equations 1 and 2:

$\begin{matrix}{Z = {{j\; x} - \frac{1}{jwC}}} & \left( {{Equation}\mspace{14mu} 1} \right) \\{x = {{wL} - \frac{1}{wC}}} & \left( {{Equation}\mspace{14mu} 2} \right)\end{matrix}$

In Equation 1, Z can represent the impedance at node n1, jx canrepresent the impedance of a transmission line between node n1 and atermination capacitor, and

$\frac{1}{jwC}$can represent the impedance of the termination capacitor. In Equation 2,wL can represent an inductive component of the impedance of thetransmission line and

$\frac{1}{wC}$can represent a capacitive component of the transmission line at afundamental frequency w. Thus, the transmission line can function as acapacitive and/or an inductive circuit element. The transmission linecan include, for example, one or more interconnects from one or morepins of the power amplifier die to a conductive trace on a packagingsubstrate. The transmission line can also include the conductive traceon the packaging substrate.

The phase of the power amplifier output at node n1 can be shifted byadjusting the impedance of the transmission line. As one example, addingan additional wirebond coupling the node n1 to a conductive trace on apacking substrate in parallel with one or more wirebonds can decreasethe inductive impedance component of the transmission line. This canshift the phase of the impedance of a particular frequency along acircuit for the particular frequency on a Smith chart. Shifting thephase of the impedance can in turn adjust the capacitive and inductivecomponents of the impedance, for example as represented by Equations 1and 2. As another example, adjusting a length of a conductive trace onthe packaging substrate can adjust the impedance of the transmissionline. By adjusting the impedance of the transmission line and/or acapacitance of a termination capacitor in a harmonic terminationcircuit, the harmonic termination circuit can be configured to terminateat a phase of a harmonic frequency of the power amplifier output at noden1.

In certain implementations, the impedance at node n1 can beapproximately 0 (short circuit) at a second harmonic and the impedanceat node n1 can appear very large or infinite (open circuit) at a thirdharmonic. For instance, a short circuit impedance can be realized bymaking the impedance equal to 0 in Equations 1 and 2. As anotherexample, when the capacitance of the transmission line approaches zero,then the impedance will appear as an open circuit according to Equations1 and 2. In some other implementations, the impedance at node n1 can bean open circuit at a second harmonic and a short circuit at a thirdharmonic. Thus, the harmonic termination circuits can be configured tomeet the needs of a desired application.

Referring to FIG. 3A, a block diagram of another power amplifier systemincluding illustrative termination circuits according to anotherembodiment will be described. Some or all of the power amplifier systemillustrated in FIG. 3A can be implemented on a power amplifier module20. The power amplifier module 20 can include a power amplifier die 24mounted on a packaging substrate 22. The power amplifier die 24 caninclude pins, such as output pins 82 a and 82 b. Although the outputpins 82 a and 82 b, respectively, are illustrated as single pins, thesepins can each represent a group of two or more pins in certainembodiments. An output of a power amplifier can be provided to theoutput pins 82 a and 82 b. The output pins 82 a and 82 b can both becoupled to the node n1 of FIG. 2. As illustrated in FIG. 2, the node n1is coupled to a collector of a GaAs bipolar transistor, an input to theoutput matching network 25 b 1, and an input of the output harmonictermination circuit 25 b 2.

The power amplifier module 20 of FIG. 3A includes an output fundamentaltermination circuit 25 b 1 that is separate from an output harmonictermination circuit 25 b 2. The fundamental termination circuit 25 b 1and the harmonic termination circuit 25 b 2 can have differentelectrical connections to an output node of a power amplifier, such asnode n1 in FIG. 2, external to the power amplifier module 24. Forinstance, different interconnects can electrically couple thefundamental termination circuit 25 b 1 and the harmonic terminationcircuit 25 b 2 to different pins of the power amplifier module 24. Thefundamental termination circuit 25 b 1 and the harmonic terminationcircuit 25 b 2 can be included in separate signal paths on the substrate22. These separate signal paths may not be electrically connected toeach other on the substrate 22 or via circuit elements external to thepower amplifier module 24. The fundamental termination circuit 25 b 1and the harmonic termination circuit 25 b 2 can be included in separatesignal paths. For instance, the output of a power amplifier can beprovided to two or more separate signal paths with one path going to thefundamental termination circuit 25 b 1 and a different path going to theharmonic termination circuit 25 b 2. The two or more separate paths caninclude a DC path that is separate from an RF path, for example, asillustrated.

The fundamental termination circuit 25 b 1 can include one or moreinterconnects 81 b, such as wire bonds and/or bumps, coupling one ormore output pins 82 b to a conductive trace the packaging substrate 22.In implementations with more than one output pin 82 b, the interconnects81 b electrically connecting the pins 82 b to the conductive trace canbe in parallel with each other. The number of interconnects 81 b (forexample, wire bonds) can be adjusted to change the inductance of theoutput fundamental termination circuit 25 b 1 so as to preventreflection of a desired frequency component of a signal on the signalpath at the output pins 82 b. Including more interconnects 81 b inparallel can reduce an effective inductance. The conductive trace cancouple the interconnect(s) 81 b in series with a capacitor. Theconductive trace can also add an inductance and/or a capacitance to thetermination circuit, for example, as discussed above. A capacitance ofthe capacitor can be selected so as to prevent reflection of a desiredfrequency component of a signal on the signal path at the output pin(s)82 b. Alternatively or additionally, an effective capacitance of thetermination circuit can be adjusted by including additional capacitor(s)in series and/or parallel with the capacitor and/or by including othercapacitive circuit elements. The effective inductance the effectivecapacitance of the termination circuit can be configured in combinationwith each other so as to increase linearity and/or PAE of the poweramplifier module 20. The effective inductance and the effectivecapacitance can be determined, for example, based on the number ofinterconnects coupled to an output pin of the power amplifier die 24,the dimensions (such as length) of a conductive trace on the substrate,and the capacitance of a capacitor mounted on the substrate.

The output harmonic termination circuit 25 b 2 includes one or moreinterconnects 81 a, such as wire bonds and/or bumps, coupling one ormore output pins 82 a to a conductive trace of the packaging substrate22. In implementations with more than one output pin 82 a, theinterconnects 81 a electrically connecting the pins 82 a to the wiretrace can be coupled in parallel. The number of interconnects 81 a (forexample, wire bonds) included in the output harmonic termination circuit25 b 2 can be configured separately from the number of interconnects 81b of the output fundamental termination circuit 25 b 1. In this way,inductance of different termination circuits can be tuned to increaselinearity and/or PAE of the power amplifier module 20. This can includematching an impedance of a fundamental frequency of a signal at the nodein the output fundamental termination circuit 25 b 1 and terminating ata phase corresponding to a harmonic frequency of the signal at the nodein the output harmonic termination circuit 25 b 2. Effectivecapacitances of the different termination circuits can also beconfigured separately and independent of each other. Because thedifferent termination circuits can be included in different signalpaths, changes to either termination circuit may not affect anothertermination circuit.

A conductive trace can couple interconnects, such as wire bonds, inseries with one or more capacitive circuit elements, such as capacitors,in the output matching network illustrated in FIG. 3A. An effectivecapacitance of the termination circuit can be selected so as to preventreflection of an other desired frequency component of a signal on thesignal path at the output pin(s) 82 a that is different from the desiredfrequency component of the signal that the output fundamentaltermination circuit 25 b 1 is configured to prevent from reflecting. Incertain implementations, the different termination circuits can includedifferent conductive traces on the substrate 22 that can add inductanceand/or capacitance to respective termination circuits. The differentconductive traces can be configured separately and independent of eachother so that each conductive trace can provide desired termination at aselected frequency. The effective inductance and the effectivecapacitance of the termination circuit can be configured in combinationwith each other so as to increase linearity and/or PAE of the poweramplifier module 20.

FIG. 3B illustrates an example substrate 22 in accordance with anembodiment. The substrate 22 can be a packaging substrate, such as alaminate substrate. The substrate 22 can be included in any of themodules discussed herein, such as the power amplifier modules 20. Thesubstrate 22 is configured to receive a plurality of components andincludes conductive traces. The dashed lines in FIG. 3B illustrate areaswhere the substrate 22 is configured to receive components. Forinstance, as illustrated the substrate 22 is configured to receive apower amplifier module 24 and a plurality of surface mounted capacitors28 a, 28 b, and 28 c. The illustrated substrate 22 also includes a firstconductive trace 27 a and a second conductive trace 27 b. As illustratedin FIG. 3B, a separation 21 separates the first conductive trace 27 afrom the second conductive trace 27 b. The separation 21 can physicallyseparate the first conductive trace 27 a from the second conductivetrace 27 b at any suitable point for a desired application. Thus, thefirst conductive trace 27 a and the second conductive trace 27 b arepart of different signal paths on the substrate 22.

The substrate 22 can be configured to implement at least a portion ofthe termination circuits discussed herein. For instance, the firstconductive trace 27 a can be included in a load line configured to matchan impedance at output node of a power amplifier die 24 at a fundamentalfrequency of the power amplifier output signal. As illustrated, thesubstrate 22 is also configured to receive a surface mounted capacitor28 a that is part of the load line. The second conductive trace 27 b canbe included in a harmonic termination circuit separate from the loadline. The harmonic termination circuit can be configured to terminate ata phase corresponding to a harmonic frequency of the power amplifieroutput. As illustrated, the second conductive trace 27 b is configuredto receive one or more surface mounted capacitors 28 b, 28 c that arepart of the harmonic termination circuit.

FIGS. 4A-4C show simulation results comparing performance of the poweramplifier module 20 of FIG. 3A to a conventional power amplifier with asingle termination circuit. As shown in FIG. 4A, the PAE increased byabout 2-3% in one embodiment of the power amplifier module 20 of FIG. 3Aover the frequency range of 1850 MHz to 1910 MHz compared to aconventional design. Moreover, in some simulations, PAE has increased 5%or more according to the principles and advantages described herein.Increases in PAE of a system can, for example, increase an amount oftime for a battery powering the system to discharge.

FIG. 4B shows an improvement in linearity, as measured by an adjacentchannel power ratio (ACPR), in one embodiment of the power amplifiermodule 20 of FIG. 3A compared to a conventional design. As illustratedin FIG. 4B, ACPR improves by about 2 to 3 dB over the frequency range of1850 MHz to 1910 MHz. Together FIG. 4A and FIG. 4B show that the poweramplifier system of FIG. 3A can improve both PAE and ACPR at the sametime.

Figure of merit (FOM) is one way to characterize overall quality of apower amplifier. FIG. 4C shows that the FOM increases from about 86 toabout 90 in one embodiment of the power amplifier module 20 of FIG. 3Aover the frequency range of 1850 MHz to 1910 MHz compared to aconventional design. Moreover, in some implementations, FOM hasincreased from about 82 to about 90 in accordance with one or more ofthe principles and advantages described herein.

Furthermore, the increase in PAE, ACPR, FOM, or any combination thereof,has been demonstrated at a number of other frequency bands, for example,1710 MHz to 1780 MHz. Simulation data indicates that separatetermination circuits for a fundamental frequency component of a signaland harmonic frequency component can increase PAE, ACPR, FOM, or anycombination thereof over a variety of frequencies in the RF spectrum andother frequency spectra. In addition, improvement in PAE, ACPR, FOM, orany combination thereof has been shown over different power levels.

Referring to FIG. 5 a block diagram illustrating a die and exampletermination circuits termination circuits according to anotherembodiment will be described. FIG. 5 illustrates that any suitablenumber of separate termination circuits can be implemented based on adesired application. Moreover, FIG. 5 illustrates that a plurality ofseparate termination circuits can be implemented at a variety of nodeswithin an electronic system, such as an input pin(s) of a die and/oroutput pin(s) of a die. Although FIG. 5 illustrates a plurality ofseparate termination circuits at in input pins of a die and output pinsof a die, any combination of features of separate termination circuitsdescribed herein can be applied to a signal at other nodes of anelectronic system, for example, within a die such as a power amplifierdie. Moreover, according to certain implementations, at least a portionof one or more of the separate termination circuits coupled to a nodecan be embodied within a die. In some of these implementations, one ormore of the separate termination circuits coupled to the node can beembodied outside the die.

As shown in FIG. 5, an electronic system 90 can include a die and aplurality of termination circuits. The electronic system 90 can beincluded, for example, in a wireless device of FIG. 1A or FIG. 1B, apower amplifier module of FIG. 1C, the like, or any combination thereof.In some implementations, a die 92 can be a power amplifier die 24. Inother implementations, the die 92 can include, for example, a frequencymultiplier, a mixer, or the like.

The die 92 can include a plurality of including input pins 94 a-94 nand/or output pins 96 a-96 n. Separate termination circuits that includeany combination of features described herein can be coupled to differentpins and/or a different groups of two or more pins. For instance, inputtermination circuits 98 a-98 n can each be configured to preventreflection of a different frequency component of a signal at a nodecoupled to one or more input pins of the die 92. Input terminationcircuits can be coupled to input pins 94 a-94 n, respectively, of thedie 92. In some implementations, an input termination circuit can becoupled to two or more input pins of the die 92. Alternatively oradditionally, two or more input termination circuits can be coupled to asingle pin of the die 92. Similarly, output termination circuits 99 a-99n can each be configured to prevent reflection of a different frequencycomponent of a signal at a node that includes one or more output pin.Output termination circuits can be coupled to input pins 94 a-94 n,respectively, of the die 92. In some implementations, an outputtermination circuit can be coupled to two or more output pins of the die92. Alternatively or additionally, two or more output terminationcircuits can be coupled to a single pin of the die 92.

Any suitable number of input pins 94 a-94 n and/or output pins 96 a-96 ncan be included on the die 92. Moreover, any suitable number of inputtermination circuits 98 a-98 n and/or output termination circuits 99a-99 n can be included in the electronic system 90. In someimplementations, the number of separate input termination circuits 98a-98 n and/or separate output termination circuits 99 a-99 n can beselected based on a desired number of harmonic frequency components toterminate.

FIG. 6 is a flow diagram of an illustrative method 50 of manufacturing amodule according to yet another embodiment. It will be understood thatany of the methods discussed herein may include greater or feweroperations and the operations may be performed in any order, asappropriate. Further, one or more acts of the methods can be performedeither serially or in parallel. For instance, the acts at blocks 54 and56 of the method 50 can be performed either serially or in parallel. Themethod 50 can be performed as part of manufacturing any of the modulesdiscussed herein, such as the power amplifier module 20.

At block 52, a die can be attached to a substrate. For instance, a poweramplifier die 24 can be attached to a packaging substrate 22.

A first interconnect between the die and a first conductive trace on thesubstrate can be formed at block 54. The first interconnect can becoupled to one or more output pins of the die. The first interconnectcan include, for example, one or more wirebonds and/or one or morebumps. In certain implementations, the first interconnect can include awirebond that is bonded to a pad of the die. According to some of theseimplementations, the wirebond can also be bonded to a finish plating ofthe substrate. The first interconnect can be included in a firsttermination circuit configured to match an impedance of a fundamentalfrequency of an output signal of the die.

A second interconnect between the die and a second conductive trace onthe substrate can be formed at block 56. The second interconnect can becoupled to one or more output pins of the die. The second interconnectcan include, for example, one or more wirebonds and/or one or morebumps. In certain implementations, the second interconnect can include awirebond that is bonded to a pad of the die. According to some of theseimplementations, the wirebond can also be bonded to a finish plating ofthe substrate. The second interconnect can be included in a secondtermination circuit configured to terminate at a phase corresponding toa harmonic of the amplified output signal.

Applications

Some of the embodiments described above have provided examples inconnection with wireless devices that include power amplifiers. However,the principles and advantages of the embodiments can be used for anyother systems or apparatus that have needs for two or more separatetermination circuits configured to prevent reflection of two or moredifferent frequency components of a signal. For example, separatetermination circuits can be implemented in connection with multipliers,such as frequency multipliers, and/or mixers instead of poweramplifiers. As another example, separate termination circuits can beimplemented at any point on a signal path at which it is desirable toseparate termination circuits for two or more different frequencycomponents, such as a fundamental frequency component and a harmonicfrequency component.

Systems implementing one or more aspects of the present disclosure canbe implemented in various electronic devices. Examples of electronicdevices can include, but are not limited to, consumer electronicproducts, parts of the consumer electronic products, electronic testequipment, etc. More specifically, electronic devices configuredimplement one or more aspects of the present disclosure can include, butare not limited to, an RF transmitting device, any portable devicehaving a power amplifier, a mobile phone (for example, a smart phone), atelephone, a base station, a femtocell, a radar, a device configured tocommunication according to the WiFi standard, a television, a computermonitor, a computer, a hand-held computer, a tablet computer, a laptopcomputer, a personal digital assistant (PDA), a microwave, arefrigerator, an automobile, a stereo system, a DVD player, a CD player,a VCR, an MP3 player, a radio, a camcorder, a camera, a digital camera,a portable memory chip, a washer, a dryer, a washer/dryer, a copier, afacsimile machine, a scanner, a multi functional peripheral device, awrist watch, a clock, etc. Part of the consumer electronic products caninclude a multi-chip module, a power amplifier module, an integratedcircuit including two or more termination circuits, a packagingsubstrate including one or more circuit elements, etc. Moreover, otherexamples of the electronic devices can also include, but are not limitedto, memory chips, memory modules, circuits of optical networks or othercommunication networks, and disk driver circuits. Further, theelectronic devices can include unfinished products.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “e.g.,” “for example,” “such as” and the like,unless specifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments is not intended to beexhaustive or to limit the invention to the precise form disclosedabove. While specific embodiments of, and examples for, the inventionare described above for illustrative purposes, various equivalentmodifications are possible within the scope of the invention, as thoseskilled in the relevant art will recognize. For example, while processesor blocks are presented in a given order, alternative embodiments mayperform routines having steps, or employ systems having blocks, in adifferent order, and some processes or blocks may be deleted, moved,added, subdivided, combined, and/or modified. Each of these processes orblocks may be implemented in a variety of different ways. Also, whileprocesses or blocks are at times shown as being performed in series,these processes or blocks may instead be performed in parallel, or maybe performed at different times.

The teachings provided herein can be applied to other systems, notnecessarily the system described above. The elements and acts of thevarious embodiments described above can be combined to provide furtherembodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. An apparatus comprising: a power amplifier dieincluding a power amplifier configured to receive a radio frequencyinput signal and to provide an amplified radio frequency signal at apower amplifier output; an output matching network electricallyconnected to the power amplifier output, the output matching networkconfigured to provide impedance matching at a fundamental frequency ofthe amplified radio frequency signal, and the output matching networkincluding a first capacitor external to the power amplifier die; and aharmonic termination circuit electrically connected to the poweramplifier output, the harmonic termination circuit configured toterminate at a phase corresponding to a harmonic frequency of theamplified radio frequency signal, the harmonic termination circuitincluding a second capacitor external to the power amplifier die, thefirst capacitor and the second capacitor having separate electricalconnections to the power amplifier die.
 2. The apparatus of claim 1wherein the power amplifier die includes a first pin and a second pin,the first capacitor being electrically connected to the first pin andthe second capacitor being electrically connected to the second pin. 3.The apparatus of claim 1 wherein the first second and the secondcapacitor are electrically connected to the power amplifier die by wayof different interconnects.
 4. The apparatus of claim 1 wherein thefirst second and the second capacitor are electrically connected to thepower amplifier die by way of different wirebonds.
 5. The apparatus ofclaim 1 wherein further comprising a substrate including a first traceand a second trace, the first trace and the second trace being externalto the power amplifier die, and the output matching network includingthe first trace and the harmonic termination circuit including thesecond trace.
 6. The apparatus of claim 5 wherein the first capacitor iscoupled to the substrate and the second capacitor is coupled to thesubstrate, the first conductive trace being in an electrical pathbetween the first capacitor and the power amplifier die, and the secondconductive trace being in an electrical path between the secondcapacitor and the power amplifier die.
 7. The apparatus of claim 1wherein the first capacitor and the second capacitor are surface mountcapacitors.
 8. The apparatus of claim 1 wherein the harmonic frequencyof the amplified radio frequency signal is a second harmonic frequencyof the amplified radio frequency signal.
 9. The apparatus of claim 1further comprising an input matching network configured to match animpedance at an input of the power amplifier and an input harmonictermination circuit configured to terminate at a phase of a harmonicfrequency of the radio frequency input signal.
 10. The apparatus ofclaim 1 further comprising an other harmonic termination circuitelectrically connected to the power amplifier output, the other harmonictermination circuit configured to terminate at a phase corresponding toa different harmonic frequency of the amplified radio frequency signalthan the harmonic termination circuit.
 11. The apparatus of claim 1wherein a portion of the harmonic termination circuit is implementedwithin the power amplifier die.
 12. An apparatus comprising: a poweramplifier die including a power amplifier configured to receive a radiofrequency input signal and to provide an amplified radio frequencysignal at a power amplifier output; an output matching networkelectrically connected to the power amplifier output, the outputmatching network configured provide impedance matching at a fundamentalfrequency of the amplified radio frequency signal, and the outputmatching network including a first conductive trace on a substrate, thefirst conductive trace being external to the power amplifier die; and aharmonic termination circuit electrically connected to the poweramplifier output, the harmonic termination circuit configured toterminate at a phase corresponding to a harmonic frequency of theamplified radio frequency signal, the harmonic termination circuitincluding a second conductive trace on the substrate, the secondconductive trace being external to the power amplifier die, and thefirst conductive trace and the second conductive trace having separateelectrical connections to the power amplifier die.
 13. The apparatus ofclaim 12 wherein the power amplifier die includes a first pin and asecond pin, the first conductive trace being electrically connected tothe first pin and the second conductive trace being electricallyconnected to the second pin.
 14. The apparatus of claim 12 wherein thefirst conductive trace and the second conductive trace are electricallyconnected to the power amplifier die by way of different wirebonds. 15.The apparatus of claim 12 wherein the substrate is a laminate substrateand power amplifier die is coupled to the substrate.
 16. The apparatusof claim 12 wherein the substrate is a packaging substrate and theapparatus is configured as a power amplifier module.
 17. The apparatusof claim 12 further comprising an antenna electrically connected to theoutput matching network, and the apparatus is configured as a mobiledevice.
 18. The apparatus of claim 12 wherein the harmonic terminationcircuit includes a capacitor that is external to the power amplifierdie, the capacitor having a first end electrically connected to thesecond conductive trace and a second end electrically connected toground.
 19. The apparatus of claim 12 wherein the harmonic frequency ofthe amplified radio frequency signal is a second harmonic frequency ofthe amplified radio frequency signal.
 20. An apparatus comprising: a dieincluding an active circuit element configured to provide an outputsignal at an output node of the die; an output matching networkelectrically connected to the output node, the output matching networkconfigured to provide impedance matching at a fundamental frequency ofthe output signal, the output matching network including a firstconductive trace on a substrate and a first capacitor electricallyconnected to the first conductive trace, the first conductive trace andthe first capacitor being external to the die; and a harmonictermination circuit electrically connected to the output node, theharmonic termination circuit configured to terminate at a phasecorresponding to a harmonic frequency of the output signal, the harmonictermination circuit including a second conductive trace on the substrateand a second capacitor electrically connected to the second conductivetrace, the second conductive trace and the second capacitor beingexternal to the die, the first conductive trace and the secondconductive trace having separate electrical connections to the die.